Distribution of Methylmercury and Inorganic Mercury in Neonate Hamsters Dosed with Methylmercury During Fetal Life

The study of the effects of methylmercury (MeHg) contamination has intensified since the MeHg outbreaks in Japan and Iraq. However, most of these studies used high doses of MeHg to obtain its most severe effects. This work identified the MeHg targets in neonate hamsters after administration of two different single oral doses of radiolabeled methylmercury chloride (Me203HgCl) to two groups of pregnant hamsters. The low-dose group received 0.05 μg of 203Hg as Me203HgCl per gram of body weight and the radioactivity was 6.6×103 Bq. The high-dose group received 0.55 μg of 203Hg as Me203HgCl per gram of body weight with 2×104 Bq. In the first day of life, the brain was the organ with the highest Me203Hg concentration, followed by the liver, kidneys, and intestines. However, these values of Me203Hg decreased at different rates in all organs until 12 days of life, whereas total 203Hg in the body did not change during the same period. This suggests an age-dependent Me203Hg body distribution instead of an elimination of Me203Hg from the body.